• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.9
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• pp.1047-1052
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• 2012

Primary water stress corrosion cracking (PWSCC) instances have been reported in the Alloy 600 reactor pressure vessel head penetration nozzle and the Alloy 82/182 dissimilar metal butt weld nozzle in several PWRs. Therefore, in-service inspection programs have been adopted worldwide to prevent failure at the weld region. If a PWSCC is observed at the dissimilar metal weld region during inspection, its structural integrity should be evaluated; however, this requires considerable time and effort, and this might lead to a decrease in the plant utilization coefficient. To prevent this, KHNP-CRI have established integrity assessment criteria and developed a computer program for the fast evaluation and judgment of PWSCC. In this paper, the results and current status of the same are presented. Through this study, criteria for the structural integrity evaluation of PWSCC have been established, and a computer program has been developed to realize technical means for the evaluation of PWSCC structural integrity.

• Journal of Advanced Navigation Technology
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• v.25 no.5
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• pp.415-425
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• 2021

In line with the trend of the digital transformation, the financial sector is providing financial services with new technologies. Among them, the open banking, which is drawing attention from global financial industry, is a service environment that maximizes customers' convenience and data utilization. In addition, the shift in the digital paradigm has also increased anxiety that security problems such as hacking and information leakage caused by data sharing are also concerned. A failure to overcome the negative view will hinder the development of financial services. This study presents a security governance system that can safely and comprehensively manage data in a digital financial ecosystem. This prepares a technical application plan by presenting a digital financial security architecture to field workers, focusing on the open banking service environment. It can be seen that this study is worthwhile by presenting a comprehensive information protection system that allows financial IT to introduce and utilize open banking services in a changing environment.

• Journal of Korean Society for Quality Management
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• v.49 no.3
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• pp.269-279
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• 2021

Purpose: The purpose of this study was to suggest weapon system specifications for requirements of Condition-Based Maintenance(CBM/CBM⁺). Methods: The military documents and case studies with regard to condition-based maintenance were reviewed. Representative Korea defense specifications of weapon system such as an aircraft, a C4ISR etc. were analyzed and investigated the level of requirement for maintainability was. Results: Condition-based maintenance was defined in both U.S. instruction and Korean directive. While deparment of defense(U.S.) provide a guidebook for CBM⁺, detailed instruction was not sufficient for Korean. Ministry of national defense(ROK) define the CBM⁺ by means of IPS element which should be developed along with the system development. The maintainability was barely included in Korean defense specifications, except for BIT(Built-in test) function. As a first step for defining the condition-based maintenance requirement in defense specification, this study suggests a standard form for data needed to acquire according to types of system, fault, failure, and so on. Conclusion: The empirical researches on CMB/CBM⁺ with domestic weapon systems are not enough, and a logic which leads the maintenance strategy to CMB/CBM⁺ is not solved. Through technical researches and institutional improvements including this study, we hope that condition-based maintenance would be fully established in the Korean defense field.

• Tribology and Lubricants
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• v.37 no.2
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• pp.48-53
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• 2021

Wind energy is considered as the most competitive energy source in terms of power generation cost and efficiency. The power train of the pitch drive for a wind turbine uses a 3-stage complex planetary gear system in being developed locally. A gear train of the pitch drive consists of an electric or hydraulic motor and a planetary decelerator, which optimizes the pitch angle of the blade for wind generators in response to the change in wind speed. However, it is prone to many problems, such as excessive repair costs in case of failure. Complex planetary gears are very important parts of a pitch drive system because of strength problem. When gears are designed for the power train of a pitch drive, it is necessary to analyze the fatigue strength of gears. While calculating the specifications of the complex planetary gears along with the bending and compressive stresses of the gears, it is necessary to analyze the fatigue strength of gears to obtain an optimal design of the complex planetary gears in terms of cost and reliability. In this study, the specifications of planetary gears are calculated using a self-developed gear design program. The actual gear bending and compressive stresses of the planetary gear system were analyzed using the Lewes and Hertz equation. Additionally, the calculated specifications of the complex planetary gears were verified by evaluating the results from the Stress - No. of cycles curves of gears.

• The Journal of the Korea Contents Association
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• v.19 no.2
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• pp.1-10
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• 2019

The present research aims to identify the issues that occurred when uploading stock photos to the internet-based stock image agencies and to develop technical solutions based on web service technologies. We identify the issues by examination of previous studies and stock photo uploading systems of major three agencies currently in service. As such, we develop web service technology by focusing on the following matters. First, we apply an automatic tag system to ensure convenience. Second, to ensure safety, we apply a technology that easily enables prevention of portrait rights violations and trademark infringements. We also prepare for measures against possible harmfulness. Third, to ensure completeness, we apply a method which resolves upload failure issues that frequently occurred in the past. In particular, the present research is significant as it applies an automatic image analysis system based on Google Cloud Vision API as the artificial intelligence-based image processing technology. In addition, we develop a web service program which improves user access by using SNS-type screen composition.

• Journal of the Korean GEO-environmental Society
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• v.19 no.12
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• pp.5-14
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• 2018

Recently, method of reinforced earth retaining wall have been proposed according to the material of facing, geosynthetic, construction method, and facing slope. However, the regulations such as the design method and detailed review items according to each construction method are not clear, and collapse due to heavy rainfall frequently occurs. In this study, to obtain a more stable technical approach in the design of reinforced earth retaining wall, the combination of the pullout failure of reinforced earth retaining wall and the optimal reinforcement ratio of height using reinforced earth retaining wall using a single strength reinforcement is assumed, optimum design of stiffener, optimal design of superimposed wall and optimum length ratio of reinforcement material of geosynthetics are proposed through safety factor according to reinforcement length ratio (L/H).

• Journal of the Korean Society of Mineral and Energy Resources Engineers
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• v.55 no.6
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• pp.546-552
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• 2018

Although there are differences in the history of mining development by country, geographical conditions, and economic status, there are various problems such as water pollution caused by acid mine drainage from past mine development, soil and water pollution caused by mine tailing, and landslides caused by slope failure. Thus, human life is threatened by ground subsidence caused by collapses. Some countries have technology and legal systems that are different from those of others. In countries where mine reclamation is underway, or has to begin, there is a need for institutional arrangements and technical support. Countries trying to start mine reclamation require help from the international community. Technically and institutionally advanced nations need to recover from mine reclamation through cooperation with countries that are beginning to undertake reclamation.

• The Journal of Bigdata
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• v.3 no.2
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• pp.1-10
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• 2018

In the field of smart water management, there is an increasing demand for strengthening competitiveness through big data analysis. As a result, systematic management (Governance) of big data is becoming an important issue. Big data governance is a systematic approach to evaluating, directing and monitoring data management, such as data quality assurance, privacy protection, data lifetime management, data ownership and clarification of management rights. Failure to establish big data governance can lead to serious problems by using low quality data for critical decisions. In addition, personal privacy data can make Big Brother worry come true, and IT costs can skyrocket due to the neglect of data age management. Even if these technical problems are fixed, the big data effects will not be sustained unless there are organizations and personnel who are dedicated and responsible for data-related issues. In this paper, we propose a method of building data governance for smart water data management based on big data.

• Journal of Korean Neurosurgical Society
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• v.62 no.1
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• pp.27-34
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• 2019

Objective : Stent-assisted coil embolization of intracranial wide-necked aneurysm requires long-term postoperative antiplatelet therapy to prevent in-stent thrombosis. This study aimed to demonstrate results of temporary stent placement for coiling wide necked small intracranial aneurysms, which eliminated need for antiplatelet agents, and to discuss its feasibility and safety. Methods : Data of 156 patients who underwent stent-assisted coil embolization between 2011 and 2014 were retrospectively analyzed. Thirteen cases of temporary stent-assisted coil embolization were included, and their clinical and radiological results were evaluated. Results : The aneurysms treated were all unruptured except one case. All of them had wide neck with mean dome-to-neck ratio of 0.96 and were small-sized aneurysms with mean maximal diameter of 4.2 mm. There was no technical failure in retrieval of stent after completion of embolization of the target aneurysm. Immediate angiography revealed 11 complete and two partial embolization (one residual neck and one residual aneurysm). Two cases encountered thrombosis complication, and they were managed without neurological sequelae. The mean follow-up period was 43 months, angiographic follow-up revealed two cases with minor recurrence, and clinical outcome was good with modified Rankin scale score of 0. Conclusion : Temporary stent-assisted coil embolization of small wide-necked intracranial aneurysm using fully retrievable stent appears safe and effective. Further application and evaluation of this technique in more cases with larger size aneurysm is warranted.

• Journal of Korean Neurosurgical Society
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• v.64 no.1
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• pp.23-29
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• 2021

Objective : Although stent-assisted coiling (SAC) has been reported to be safe and effective in treating wide-necked aneurysms, the technique has procedure-related complications. Thus, we reported our experiences of SAC using the Neuroform Atlas stent in treating wide-necked aneurysms and evaluated the incidence of and risk factors for procedure-related complications. Methods : From March 2018 to August 2019, we treated 130 unruptured wide-necked aneurysms in 123 patients with Neuroform Atlas stents. Angiographic results and clinical outcomes were reviewed retrospectively. Clinical and angiographic follow-up were performed in all cases (mean, 12.4 months) after the procedure. Results : There were eight cases (6.2%) of procedure-related complications (two dissections, five thromboembolisms, and one hemorrhage) and two (1.5%) of delayed complications (one ischemia and one hemorrhage). There was one case (0.8%) of failure of stent deployment and one (0.8%) of suboptimal positioning of the stent. Follow-up angiography showed complete obliteration in 103 (79.2%), residual neck in 16 (12.3%), and residual aneurysm in 11 cases (8.5%). Aneurysm locations in the middle cerebral artery (odds ratio [OR], 2.211; p=0.046) and the anterior communicating artery (OR, 2.850; p=0.039) were associated with procedure-related complications on univariate analysis. However, no independent risk factor for procedure-related complications was noted in multivariate analysis. Conclusion : The Neuroform Atlas showed a high rate of technical success. Good clinical and radiographic outcomes in early follow-up suggests that the device is feasible and safe. SAC of aneurysms on the middle cerebral artery or anterior communicating artery may require more attention to prevent possible procedure-related complications.